reduce emacs dependency

[Mark Brethen]

I have a dependency on the emacs-app for the reduce-addons subport. It is needed to byte-compile a couple of elisp files for the ide.  I realize there are currently 8 different ports that install emacs:

emacs @24.5_1 (editors)
    The GNU Emacs text editor

emacs-app @24.5_2 (aqua, editors)
    The GNU Emacs text editor (Cocoa version)

emacs-app-devel @20151029 (aqua, editors)
    The GNU Emacs text editor, recent Git development version

emacs-mac-app @5.15 (aqua, editors)
    Emacs Mac port

emacs-snapshot @20140101_1 (editors)
    The GNU Emacs text editor

emacs22 @22.3_8 (editors)
    The GNU Emacs text editor

emacs23 @23.4_6 (editors)
    The GNU Emacs text editor

xemacs @21.4.22_11 (editors, x11)
    A highly customizable open-source text editor.

A user who uses xemacs, for example, may not like another emacs app installed on their mac. Is it preferable to check if emacs is already installed on the user’s system and if not, then install a “default” emacs app or the emacs binary? What’s the best way to implement this?


Mark